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From: TSS ()
Subject: TAFS1 Position Paper on Atypical scrapie and Atypical BSE
Date: July 9, 2007 at 1:38 pm PST

TAFS1 Position Paper on Atypical scrapie and Atypical BSE


TAFS

INTERNATIONAL FORUM FOR TRANSMISSIBLE ANIMAL DISEASES AND FOOD SAFETY

a non-profit Swiss Foundation

(May 16, 2007)

TAFS1 Position Paper on Atypical scrapie and Atypical BSE

In recent years there have been a small number of reports in the scientific literature that
unusual isolates of BSE have been detected in cattle in various countries around the world. In
addition, following the introduction of enhanced surveillance programmes for scrapie in small
ruminants in Europe, unusual or unexpected results were also widely reported. In both
instances, the shortage of scientific data at the time did not enable scientists to precisely
identify what they were dealing with. Because of similarities with the diseases that they were
searching for, namely BSE in cattle and scrapie in sheep, the immediate response was to call
the isolates “atypical BSE” and “atypical scrapie” for reasons that will be explained below.
Some additional local terminology was applied in some countries, but for the moment the
term “atypical” is more commonly applied. This paper aims to provide the background to
these findings, and explain their signficance.


snip...


Is it transmissible?

�� Experimentally, it has been shown that it can be transmitted to genetically modified
mice(28), and by intracerebral inoculation to sheep (unpublished work in progress).
�� These transmissions do not prove that it will transmit naturally from sheep to sheep,
but studies involving oral infection of sheep are under way.
�� Although most atypical cases occur singly in flocks, there are some instances where
two affected sheep have been identified in flocks. This may indicate that natural
transmission may occur, or that the sheep were infected from a common alternative
source(22, 29). Possible indications of an association with the feeding of vitamins and
mineral feed supplements were detected in Norway, but remain to be proven(22).

Does it represent a risk to human health?

Does it represent a risk to human health?

�� This is currently unknown, but if atypical scrapie is not a new phenomenon, and has
simply been discovered recently, then the lack of epidemiological association between
TAFS
6
prion diseases in humans and sheep, or consumption of sheep products, suggest that
atypical scrapie does not represent a risk to humans. This is not however
demonstration of absolute safety.
�� This is currently unknown, but if atypical scrapie is not a new phenomenon, and has
simply been discovered recently, then the lack of epidemiological association between
TAFS
6
prion diseases in humans and sheep, or consumption of sheep products, suggest that
atypical scrapie does not represent a risk to humans. This is not however
demonstration of absolute safety.


======================================================


PLEASE NOTE ;


EVIDENCE OF SCRAPIE IN SHEEP AS A RESULT OF FOOD BORNE EXPOSURE

This is provided by the statistically significant increase in the incidence
of sheep scrape from 1985, as determined from analyses of the submissions
made to VI Centres, and from individual case and flock incident studies.
........


http://www.bseinquiry.gov.uk/files/yb/1994/02/07002001.pdf


1: J Infect Dis 1980 Aug;142(2):205-8


Oral transmission of kuru, Creutzfeldt-Jakob disease, and scrapie to nonhuman primates.

Gibbs CJ Jr, Amyx HL, Bacote A, Masters CL, Gajdusek DC.

Kuru and Creutzfeldt-Jakob disease of humans and scrapie disease of sheep and goats were transmitted to squirrel monkeys (Saimiri sciureus) that were exposed to the infectious agents only by their nonforced consumption of known infectious tissues. The asymptomatic incubation period in the one monkey exposed to the virus of kuru was 36 months; that in the two monkeys exposed to the virus of Creutzfeldt-Jakob disease was 23 and 27 months, respectively; and that in the two monkeys exposed to the virus of scrapie was 25 and 32 months, respectively. Careful physical examination of the buccal cavities of all of the monkeys failed to reveal signs or oral lesions. One additional monkey similarly exposed to kuru has remained asymptomatic during the 39 months that it has been under observation.

PMID: 6997404
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6997404&dopt=Abstract


=====================================================


snip...


Where has atypical BSE been found?

�� Although the greatest number of cases is in France(12), increasing numbers of cases
have now been identified in other countries – Canada (1), Germany (2), Italy (2),
Japan (2), Netherlands (4), Poland (7), Sweden (1), Switzerland (1), UK (1), and USA
(2). In Sweden and the USA the atypical cases represent the only indigenous cases
detected. In other words – typical BSE has not been detected in native cattle in these
two countries (34).
�� In France, Poland, Netherlands and Germany both H and L forms of atypical BSE
have been reported(25).

Is there anything else unusual about the cases?

�� Yes. With the exception of the first Japanese case, others have generally occurred in
old cows – 8 to 18 years reported in France, 11 and 15 in Italy. Most BSE cases occur
in animals between the age of four and six, although very young and very old animals
can be affected too.
�� In one case, still unpublished, a mutation of the PrP gene has been detected, similar to
one found in one form of CJD in humans.It has to be stressed that this has not been
identified in every case of atypical BSE, although not all have been analysed in this
way.


snip...


Where has atypical BSE been found?

�� Although the greatest number of cases is in France(12), increasing numbers of cases
have now been identified in other countries – Canada (1), Germany (2), Italy (2),
Japan (2), Netherlands (4), Poland (7), Sweden (1), Switzerland (1), UK (1), and USA
(2). In Sweden and the USA the atypical cases represent the only indigenous cases
detected. In other words – typical BSE has not been detected in native cattle in these
two countries (34).
�� In France, Poland, Netherlands and Germany both H and L forms of atypical BSE
have been reported(25).

Is there anything else unusual about the cases?

�� Yes. With the exception of the first Japanese case, others have generally occurred in
old cows – 8 to 18 years reported in France, 11 and 15 in Italy. Most BSE cases occur
in animals between the age of four and six, although very young and very old animals
can be affected too.
�� In one case, still unpublished, a mutation of the PrP gene has been detected, similar to
one found in one form of CJD in humans.It has to be stressed that this has not been
identified in every case of atypical BSE, although not all have been analysed in this
way.

TAFS
9

Is there more than one strain of atypical BSE?

�� At this stage it is too early to say, but there are early indications that this may be so.
Caution is needed because there is a need to be certain that the variations in results are
not artifacts, either generated by differences in test methods between countries, or due
to degradation of samples before they are tested. This has been shown to generate
variations in blotting patterns, but is unlikely to have produced the extensive
variations seen in the Italian cases or the H form detected in France and elsewhere.
�� So the key to confirming whether or not H and L isolates actually represent different
strains will be further characterization following transmission to laboratory rodents
and/or cattle. These are the methods normally used to characterize prion strains
comprehensively.
�� This will also help to confirm the extent to which the atypical BSE cases differ from
BSE. In the meantime, especially if it proves possible to transmit isolates to other
animals, additional biochemical methods can be used to investigate other aspects of
prion protein biology of the different isolates.
�� Two publications have already highlighted the difficulties of interpreting data on
biological transmissibility. One demonstrates that BSE and “H-type” BSE are
different, based upon their behaviour in genetically modified mice, examination of
fixed and unfixed brain tissue, and comparison of incubation periods(6). The other,
studying “L-type” BSE (Italian BASE), and using different mouse models,
acknowledges apparent differences between it and BSE when first inoculated into
mice, but claims that further transmission from mouse to mouse by inoculation
produces a strain indistinguishable from BSE (by the limited criteria used in the study)
(11).
�� These findings suggest that it may prove possible to understand the relationship
between BSE and atypical BSE isolates, and between the criteria used to classify them
at present, and the actual strain of prion that infects the animal.

Is atypical BSE transmissible?

�� Investigations are under way in France, Italy, Germany and Japan. Experimental
transmissibility to cattle and primates has now been demonstrated for L-type BSE, and
to mice for both H and L types (3, 6, 11). Some of this work remains incomplete and
unpublished at the time of writing.
�� This does not prove that atypical BSE transmits from animal to animal naturally.
Does it represent a risk to human health?
�� It is too early to tell whether or not it represents a risk to humans. For the moment it is
assumed to be a danger, and is treated like BSE. Results of experimental transmission
to primates remain unpublished. Some scientists suggest that similarities between the
molecular features of H-type BSE and some prion diseases of humans may indicate
that they are related. Care must be exercised in interpreting such preliminary data(8)
specifically with regard to suggestions of a cause and effect.
�� Transmissibility to cattle has been confirmed, but remains currently unpublished as the
study is incomplete. It may therefore be possible to investigate further, by oral
challenge, whether or not the infectious agent is distributed around the body in a
different way from BSE, possibly infecting tissues that are not considered-infectious
in BSE. This may have implications for risk management and public health.
�� It is however important to remember that so far only small numbers of atypical BSE
cases have been detected compared to the many thousands of BSE cases
TAFS
10

�� Depending on how atypical BSE cases arise, they may represent a long term problem
when BSE has been eradicated, or they may disappear along with BSE because the
controls are equally effective in preventing spread of infection. As transmissibility to
cattle has now been partially demonstrated, it can be presumed that atypical BSE may
transmit to cattle orally through feed, in which case rendering and feed controls should
prevent further transmission by that route.

What is the impact of this finding on measures to control BSE, and to protect
consumers?

�� At the moment all measures in place to protect cattle and humans from becoming
infected with BSE are considered adequate to protect against atypical BSE. Tests used
to detect BSE in cattle have detected the atypical cases too, and on brain tissue, which
is already defined as SRM in countries where controls are in place.
�� Care will be needed in relaxing such controls, especially if atypical BSE proves to be
transmissible directly between cattle, or to humans via tissues that are not currently
defined as SRM.
�� Similarly, if atypical BSE is demonstrated to arise spontaneously, rare sporadic cases
may be expected to occur in all countries with significant cattle populations. This in
itself will challenge expectations of total eradication as a result of controls.
Nevertheless, the existence of sporadic cases would indicate potential to give rise to
further large epidemics if some protective measures are not maintained indefinitely.
These may involve prohibitions on the use of certain proteins in animal feed, more
rigorous rendering processes, and possibly continued removal and destruction of
certain SRM from human food and animal feed chains.


snip...


http://www.tseandfoodsafety.org/position_papers/TAFS_POSITION_PAPER_ON_ATYPICAL_SCRAPIE_AND_%20ATYPICAL_BSE_070516.pdf


PLEASE NOTE;


USA MAD COW STRAIN MORE VIRULENT TO HUMANS THAN UK STRAIN

18 January 2007 - Draft minutes of the SEAC 95 meeting (426 KB) held on 7
December 2006 are now available.


snip...

64. A member noted that at the recent Neuroprion meeting, a study was
presented showing that in transgenic mice BSE passaged in sheep may be more
virulent and infectious to a wider range of species than bovine derived BSE.

Other work presented suggested that BSE and bovine amyloidotic spongiform
encephalopathy (BASE) MAY BE RELATED. A mutation had been identified in the
prion protein gene in an AMERICAN BASE CASE THAT WAS SIMILAR IN NATURE TO A
MUTATION FOUND IN CASES OF SPORADIC CJD.


snip...

http://www.seac.gov.uk/minutes/95.pdf


3:30 Transmission of the Italian Atypical BSE (BASE) in Humanized Mouse

Models Qingzhong Kong, Ph.D., Assistant Professor, Pathology, Case Western Reserve
University

Bovine Amyloid Spongiform Encephalopathy (BASE) is an atypical BSE strain
discovered recently in Italy, and similar or different atypical BSE cases
were also reported in other countries. The infectivity and phenotypes of
these atypical BSE strains in humans are unknown. In collaboration with
Pierluigi Gambetti, as well as Maria Caramelli and her co-workers, we have
inoculated transgenic mice expressing human prion protein with brain
homogenates from BASE or BSE infected cattle. Our data shows that about half
of the BASE-inoculated mice became infected with an average incubation time
of about 19 months; in contrast, none of the BSE-inoculated mice appear to
be infected after more than 2 years.

***These results indicate that BASE is transmissible to humans and suggest that BASE is more virulent than
classical BSE in humans.***


6:30 Close of Day One


http://www.healthtech.com/2007/tse/day1.asp


SEE STEADY INCREASE IN SPORADIC CJD IN THE USA FROM
1997 TO 2006. SPORADIC CJD CASES TRIPLED, with phenotype
of 'UNKNOWN' strain growing. ...


http://www.cjdsurveillance.com/resources-casereport.html

There is a growing number of human CJD cases, and they were presented last
week in San Francisco by Luigi Gambatti(?) from his CJD surveillance
collection.

He estimates that it may be up to 14 or 15 persons which display selectively
SPRPSC and practically no detected RPRPSC proteins.


http://www.fda.gov/ohrms/dockets/ac/06/transcripts/1006-4240t1.htm


http://www.fda.gov/ohrms/dockets/ac/06/transcripts/2006-4240t1.pdf


Diagnosis and Reporting of Creutzfeldt-Jakob Disease

Singeltary, Sr et al. JAMA.2001; 285: 733-734.

http://jama.ama-assn.org/http://www.neurology.org/cgi/eletters/60/2/176#535


BRITISH MEDICAL JOURNAL

BMJ

http://www.bmj.com/cgi/eletters/319/7220/1312/b#5406


BMJ

http://www.bmj.com/cgi/eletters/320/7226/8/b#6117


JOURNAL OF NEUROLOGY

MARCH 26, 2003

RE-Monitoring the occurrence of emerging forms of Creutzfeldt-Jakob

disease in the United States

Email Terry S. Singeltary:

flounder@wt.net

I lost my mother to hvCJD (Heidenhain Variant CJD). I would like to

comment on the CDC's attempts to monitor the occurrence of emerging

forms of CJD. Asante, Collinge et al [1] have reported that BSE

transmission to the 129-methionine genotype can lead to an alternate

phenotype that is indistinguishable from type 2 PrPSc, the commonest

sporadic CJD. However, CJD and all human TSEs are not reportable

nationally. CJD and all human TSEs must be made reportable in every

state and internationally. I hope that the CDC does not continue to

expect us to still believe that the 85%+ of all CJD cases which are

sporadic are all spontaneous, without route/source. We have many TSEs in

the USA in both animal and man. CWD in deer/elk is spreading rapidly and

CWD does transmit to mink, ferret, cattle, and squirrel monkey by

intracerebral inoculation. With the known incubation periods in other

TSEs, oral transmission studies of CWD may take much longer. Every

victim/family of CJD/TSEs should be asked about route and source of this

agent. To prolong this will only spread the agent and needlessly expose

others. In light of the findings of Asante and Collinge et al, there

should be drastic measures to safeguard the medical and surgical arena

from sporadic CJDs and all human TSEs. I only ponder how many sporadic

CJDs in the USA are type 2 PrPSc?

http://www.neurology.org/cgi/eletters/60/2/176#535


doi:10.1016/S1473-3099(03)00715-1
Copyright © 2003 Published by Elsevier Ltd.
Newsdesk

Tracking spongiform encephalopathies in North America

Xavier Bosch

Available online 29 July 2003.


Volume 3, Issue 8, August 2003, Page 463


“My name is Terry S Singeltary Sr, and I live in Bacliff, Texas. I lost my
mom to hvCJD (Heidenhain variant CJD)
and have been searching for answers ever since. What I have found is that we
have not been told the truth. CWD
in deer and elk is a small portion of a much bigger problem.”
............................


http://www.thelancet.com/journals/laninf/article/PIIS1473309903007151/fulltext

http://download.thelancet.com/pdfs/journals/1473-3099/PIIS1473309903007151.pdf


see history of cjd questionnaire

http://brain.hastypastry.net/forums/showthread.php?t=2408


sporadic CJD, the big lie ;


see full text ;


http://lists.ifas.ufl.edu/cgi-bin/wa.exe?A2=ind0705&L=sanet-mg&T=0&P=25276


TSS




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